Bike computers are often used by cyclists to monitor the time, distance and speed of a bicycle. Typically, these devices include a sensor mounted adjacent a wheel or a pedal assembly of the bicycle. A computer or display unit is mounted on the handlebars of a bicycle to provide a visual display for the rider. The computer and the sensor are hard wired together to allow for the transmission of data from the sensor to the computer. It can be appreciated that the wiring of a device on a bicycle is a time consuming task. Further, the results may not provide sufficient durability for those bicycles operated in rough terrains and may not be aesthetically pleasing.
By way of example, Tsuyama, U.S. Pat. No. 4,633,216 discloses a running data display unit for a bicycle that calculates running data such as running speed, running distance, average speed and maximum speed of a bicycle, based on pulse signals from revolution detecting devices, such as the ones provided for in Webster, U.S. Pat. No. 4,074,196. Each revolution detecting devices includes a sensor and a magnet base. The sensor is fixed at the top of a fork supporting the front wheel of the bicycle and the magnet base is fixed to a spoke of a wheel. For each revolution of the front wheel, the magnet base passes the sensor, and as a result, a lead switch in the sensor is activated so as to provide a pulse signal to a computer in the main body. A similar revolution detection device may be mounted to the crank to provide similar information to the computer. The computer and the revolution detection devices are electrically connected by means of connecting wires. Given the time required to mount the data display unit to the bicycle and to run the connecting wires between the components, it would be highly desirable to provide a detection system that overcomes the structural limitations of the prior art.
Therefore, it is a primary object and feature of the present invention to provide a wireless, passive wheel-speed and cadence detection system.
It was a further object and feature of the present invention to provide a wireless, passive wheel-speed and cadence detection system that is simple to install and inexpensive to manufacture.
It is a still further object and feature of the present invention to provide a wireless, passive wheel-speed and cadence detection system that overcomes the limitations of prior art systems.
In accordance with the present invention, a detection system is provided for measuring a cadence of an operator pedaling a bicycle. The bicycle has a frame supporting a pedal assembly. The detection system includes a cadence circuit operatively connected to the bicycle for measuring the cadence of the operator pedaling the bicycle and for generating a cadence signal corresponding to the measured cadence. A transmission circuit generates a radio frequency signal corresponding to the cadence signal and transmits the radio frequency signal to a target.
The cadence circuit includes a sensing circuit mounted one of the frame and the pedal assembly. The cadence circuit also includes an inducement element mounted to the other of the frame and the pedal assembly. The inducement element causes the sensing circuit to generate an electrical signal in response to a revolution of the pedal assembly. It is contemplated for the inducement element to be a magnet.
In a first embodiment, the sensing circuit includes a pickup coil generating an induced signal in response to the inducement element passing in proximity thereto. In addition, the sensing circuit includes a transformer operatively connected to the pickup coil for transforming the induced signal and providing the transformed induced signal to the transmission circuit as the cadence signal. The transformer has a primary coil electrically connected to the pickup coil and a secondary coil operatively connected to the transmission circuit. The transmission circuit includes an inductor and a capacitor circuit connected in parallel with the inductor. The target includes a controller connectable to the bicycle. The controller receives the radio frequency signal transmitted by the transmission circuit and converts the radio frequency signal to a cadence value for visual display.
In an alternate embodiment, the sensing circuit includes a power source for generating electrical power and a reed switch operatively connecting the power source to the transmission circuit. The reed switch is movable in response to the inducement element passing in proximity thereto between an open configuration and a closed configuration wherein the electrical power generated by the power source is provided to the transmission circuit as the cadence signal.
The bicycle also includes a fork assembly mounted to the frame and a wheel rotatably supported on the fork assembly. It is contemplated for the detection circuit to also include a second cadence circuit operatively connect to the fork assembly for generating a second cadence signal representative of a wheel speed of a wheel and a second transmission circuit for generating a second radio frequency signal corresponding to the second cadence signal and transmitting the second radio frequency signal to the target.
In accordance with a further aspect of the present invention, detection system is provided for measuring the rate of rotation of a rotating component of a bicycle. The detection system includes a sensor arrangement having a first portion mounted on the bicycle and a second portion mounted on the rotating component. The sensor arrangement generates a cadence signal representative of a revolution of the rotating component. A transmitter circuit is operatively connected to the sensor arrangement for converting the cadence signal to a radio frequency signal and for wirelessly transmitting the radio frequency signal. A controller receives the radio frequency signal and translates the radio frequency signal to a value indicative of a rate of rotation of the rotating component.
The controller includes a receiver configured to receive the radio frequency signal transmitted by the transmitter circuit. The first portion of the sensor arrangement includes a sensing circuit mounted to the bicycle and the second portion of the sensor arrangement includes an inducement element mounted to the rotating component. The inducement element causes the sensor circuit to generate an electrical signal in response to a revolution of the rotating component.
In a first embodiment, the sensing circuit includes a pickup coil that generates the electrical signal in response to the inducement element passing in proximity thereto. The sensing circuit also includes a transformer operatively connected to the pickup coil for transforming the electrical signal and providing the transformed electrical signal to the transmitter circuit as the cadence signal. In an alternate embodiment, the sensing circuit includes a power source for generating electrical power and a reed switch operatively connecting the power source to the transmission circuit. The reed switch is movable in response to the inducement element passing in proximity thereto between an open configuration and a closed configuration wherein the electrical power generated by the power source is provided to the transmission circuit as the cadence signal.
The bicycle also includes a fork assembly mounted to the frame and a wheel rotatably supported on the fork assembly. It is contemplated for the detection circuit to also include a second cadence circuit operatively connect to the fork assembly for generating a second cadence signal representative of a wheel speed of a wheel and a second transmission circuit for generating a second radio frequency signal corresponding to the second cadence signal and transmitting the second radio frequency signal wirelessly to the target.
In accordance with a still further aspect of the present invention, a method is provided for measuring a rate of rotation of a rotatable component of a bicycle. The bicycle includes a frame to which the component is rotatably mounted. The method includes the steps of detecting a revolution of the rotatable component and generating an electrical signal in response thereto that is representative of the detected revolution of the rotatable component. The electrical signal is converted to a radio frequency signal and a rate of rotation of the component is determined in response to the radio frequency signal.
It is contemplated to wirelessly transmit the radio frequency signal prior to the step of determining the rate of rotation and to transform the electrical signal prior to step of converting the electrical signal. The rotatable component may be a pedal assembly of the bicycle or may be a wheel rotatably supported by the frame of the bicycle.